S-acyloxy pyrazqles and method foe



Patented July 26, 1949 -ACYLOXY PYRAZQLES AND METHOD FOR MAKING SAME Elmore Louis Martin, Wilmington, Del., assignor to E. I. du Pont de Nemours & Company, Wilmington, Del., a corporation of Delaware No Drawing. Application May 3, 1946, Serial No. 667,125

11 Claims.

This invention relates to amidoaldehydes containing a 5-acyloxypyrazole nucleus and to acetals thereof with alkanols of 1 to 4 carbon atoms and 1,2- and 1,3-dihydroxyalkanes of 2 to 4 carbon atoms and to their preparation.

An object of this invention is to provide a new class of pyrazole compounds. Another object is to provide a class of pyrazole derivatives which are useful as dye intermediates. A related Object is to provide such derivatives which are useful as color formers. A further object is to provide 5-acyloxypyrazoles with aldehyde groups which can be reacted with vinyl alcohol polymers to form acetals without side reactions. A related object is to provide 5-acyloxypyrazoles with lower acetal groups which can be reacted with vinyl alcohol polymers to form acetals thereof, without side reactions. A further object is to provide a new class of magenta c0101 formers. Still other objects will be apparent from the following description of the invention.

The above objects are accomplished with the preparation of a novel class of 5-acyloxypyrazoles which contain an aldehyde group or a corresponding acetal group in at least one of the 1 and 3 positions of the pyrazole ring. These compounds can be made by reacting a fi-acyloxypyrazole containing a reactive group in at least one of the 1 and 3 positions with an acetal of an aldehyde containing a group of opposite function and, if desired, converting the acetal group to the free aldehyde. For example, a 5-aoyloxypy azole containing an acid halide, and especially an acid chloride, group in at least one of the 1 and 3 positions is reacted with an acetal of an aminoaldehyde under amidating conditions, e. g., in the presence of an acid binding agent, such as an organic base. The 5-acyloxypyrazole acid halides should be free from acid halide-reactive groups, e. g., reactive methylene groups, amino groups, thiol groups, etc. 7

The reaction between the 5-acyloxypyrazole containing at least one acid halide group and the acetal of the aminoaldehyde is preferably carried out at a temperature from 10 to 30 C. in the presence of a solvent or diluent medium which permits more intimate contact between the reactants. Suitable solvents for carrying out the amidation reaction include dioxane, acetone, methanol, ethanol, ethylene glycol diethyl ether, and mixtures of such solvents with water. The

reactants may be in solution or suspension in the medium. A practical manner of carrying out the reaction consists in gradually adding a solution of the acid halide in a water-miscible solvent to an aqueous suspension of an aminoaldehyde or acetal in the presence of an alkali metal carbonate solution at a temperature from -5 to 5 C.

The acetals of the lower aliphatic alcohols, i. e., alcohols containing 1 to 4 carbon atoms, are preferred. Included in this class are acetals of aliphatic monohydric alcohols and dihydric alcohols in which the two hydroxyl groups are in the 1,2- and 1,3-positions. Of these, because of their stability, ease of obtaining in crystalline form, and economy, I prefer the ethylene glycol acetals.

The 5-acyloxypyrazole amidoaldehydes and acetals which can be made from the 5-acyloxypyrazoles which contain an acid halide group in at least one of the positions 1 and 3 of the pyrazole ring are represented by the general formula:

wherein Y is a member taken from the group consistin of carbonyl (CO--) and sulfonyl (SOz-) radicals; R-Y-- is an acyl radical; R is a divalent organic radical linked by "hydrocarbon carbon atoms (viz. having hydrogen or hydrocarbon groups attached thereto) to the cyclic carbon or nitrogen atom and to Z and Z as shown; and Z and Z are members taken from the group consisting of hydrogen, amidoaldehyde, and amidoacetal groups. However, one of the groups Z and Z must contain an amidoaldehyde or acetal group. R in Formula 1 is a divalent aliphatic, aromatic, or heterocyclic nucleus but may consist of two such nuclei joined by a bivalent bridging radical, e. g., -0-, --S, -CO, SO2, SO2NH-, and CONII.

The compounds just described fall within two general classes of amidoaldehydes and their acetals with monohydric alcohols of 1 to 4 carbon atoms and 1,2- and 1,3-dihydric alcohols of 2 to 4 carbon atoms. In one case the amido acetal or aldehyde group is in the 1-position in the as in Formula is ammovalent Thydrpcar aqueous solutionrof a mineral acid such as dilute bon nucleus, and B has the same significance-as.

R. but need not be identical.

The preferred compounds Inavberepresented by the formula:

wherein Y, R, and B. have. the same significance e15" 4 chloride or sodium chloride. When the acid group is a carboxylic acid, the reaction product may be isolated by the addition of a mineral acid, for example, hydrochloric acid, sulfuric acid, or by the addition of an organic acid, for example, formic acid, acetic acid. In either case the reaction product is purified by crystallization.

The preparation of these reactants is more fully described in application Serial No. 657,629

filed March '27, 1946.

When the- 5-acyloxypyrazoles containing: an acid halide group in the 1- or 3-position are reacted with amino acetals' as described above, the

7 resulting amido acetals can be converted to the corresponding aldehydes by hydrolysis of the acetal group. This may be done by means of an hydrochloric, sulfuric, or phosphoric acid at room temperature; However, the lower acetals are ,usefulmr many purposes and can be usedfor theepreparation of higher acetals, e, g., acetals of polyvinyl alcohol, with results similar to the free wherein .Y is a carbonyl .or sulfonyl radical; A?

is a divalent hydrocarbonnucleus which isattached to the l-nitrogen atom throughan aromatic hydrocarbon radical; B is a phenylene radical; and R' is a member of the group con- -sisting of: alkyl of 1 to 3 .carhonatoms, alk-oxy. radicals of 1' to 2 carbon atoms, phenyl; methylphenyl, and ethylphenyi These compounds are preferred because the reactant materials are ccmmercially available and, what, is more important, the resulting azomethine dyes have sue;

perior color characteristics for color photg-' substituents which are common'in color formers and do not enter intodye coupling reactions,

Formulae 1,

aldehydes.

The invention will be further illustrated by the following examples; The parts. are by weight. I I 7 EXAMPLE vI m-[p-(-ethyZcarbondto-3-methyZ-lmymzolyl) benzamido] benzaidehyde e t h f Z 2 n e glycol V acetal A-solution'of 92.5 parts of l-(4-chloroormyl- 'phenyll-Zi-methyl-5-pyrazo1yl ethyl carbonate prepared as described in Example ,I of copend- .ing :application'Serial'No. 657,629.1fi1ed March 27, w

.1946, in'150 parts of anhydrous dioxane is added drcpwise during: 15. minutes tov .a vigorously stirred "suspension of 60 parts of m-aminobenzthe reaction mixture is maintained at 0-3 C. by 7 aldehyde ethylene glycol acetal,'45 parts of anhydrous potassium .carbonate, 375 parts of water, andgl50 parts of dioxane. The temperature of externai' cooling. In about minutes, after -the addition of the acid chlorideiscompleted,

crystals of the amidoacetal begin to separate.

mixture is stirred for an additional period- ,of one hour. the temperature being maintained e, g., methoxy, alkyl, aryl, halogen, and nitro-;-

groups but should be free from aldehyde reactive groups as above described.

A convenient and practical method for the preparation of the acid halides of 5-acyloxypyrazoles described above'consists in reacting a fi-pyrazolone containing a car'boxyl-ic or sulionic' acid group in the l-and/or 3-position with an organic carboxylic orsulfonic acid chloride or bromide free from ketaldone reactive groups in an aqueous alkalinesol'ution, isolating theresultingfieacyloxypyrazole either-as the pure acid v or as an alkali metal salt and converting'the acid group to an acid halide group. It' is genera-11y desirable to use at least one mol of alkali, e. g., -alkaii metal hydroxide, peracid group and at least one mol of organic acid halide and, preferably, a. slight excess, e. g., 1.2 mols, per mol, of 5-pyrazolone. 7

"compound per acid grouprepresents a practical "range.

From 1.0 to 2.5mols' of alkaline The acylation reaction is preferably carried out at'temperatures from -5 to -'C and im a length oftime sufficient to permit complete utilizationof the acid halide. When the. acid group is a sulfonic acid, the-reaction product is best insolated as thepotassi-um or sodium salt of the sulfonicacid. This is accomplished by "salting out, i. -e., the addition of potassium at 3 0. The nearly colorless microscopic. crystalsarecollected,washed thoroughly with Water, and airdriedh The. yield of the compound'which -melts.-.at.1l8-l2'0 c, is 124 parts. It has the ahove-entitledname and the probable formula:

o-om O-GHz \NLO-WNHG For purificationthe compound is dissolved .in 450 parts. of benzene, the solution treated with decol orizing charcoal and after, the .filtrate has been concentrated to aboutone-half its original'vo'lume and isallowedto cool, 112 parts of colorless A'naly'sis, calculatedifor Cz'sHzaOsNs:

crystals melting at 120-122 C. are obtained. 0:63.13; H 5. 30'; N=9;6l. Found: C=63.33, 63.38; H=5. 60,5.77;'N.=9.95.

Ihe compound, of the. preceding paragraph can be converted to m-[p-(5-ethylcarbonato-3- methyl-1 -pyrazolyl) benzamidolben'zaldehyde by the following method: ,To a solution of 50 parts or mlp fi-ethylcarbonato-3 methy1-l-pyrazolyl) benzamidolbenzaldehyde ethylene glycol acetal in ISO-parts of acetoneat 30 C. is added in one portion parts'of 10% hydrochloric acid. The solutions aremixed thoroughly and stirred for aboutone minute'during which time nearly 1201- ing at 164-165 orless crystals of the aldehyde separate. The mixture is stirred occasionally for a period of about four minutes, then is cooled to 20 C. and

an additional quantity of 50 parts of 10% hydrochloric acid is added. After mixing thoroughly a suflicient quantity of crushed ice is added directly to the reaction mass to bring its temperature to C. The resulting crystalline product is collected, washed free of acid and is air dried. The yield of material melting at 134-136 C. is quantitative. For purification the product is dissolved in 160 parts of acetone at 40 C., 70-100 parts of water are added and the solution is treated with decolorizing charcoal. The colorless filtrate is heated to 38 C. and a sufilcient volume of water (70-100 parts) is added to induce crystallization. The mixture is allowed to stand undisturbed for several minutes at room temperature and then is cooled to 0 C. with occasional stirring. The colorless fine needles are collected and air dried. The yield of compound melting at 135-136 C. is 42 parts. Analysis, calculated for C21H19O5N32 0:64.11; H=4.'76; N=10.68. Found: 0:64.55, 64.52; 11:4.79, 4.89; N=l0.59, 10.62.

ExAMPLr: II

m-[p-(-beneoxy 3 methyl 1 pymzolyl) benzenesulfonamido]benzaldehyde ethylene glycol acetal To a stirred suspension of 85 parts of m-aminobenzaldehyde ethylene glycol acetal, 130 parts of water, 40 parts of dioxane, and 69.5 parts of anhydrous potassium carbonate cooled to -5 C. by means of external cooling is added dropwise a solution of 189 parts of 1-(4'-chlorosulfophenyl))-3-methyl-5pyrazolylbenzoate prepared by the procedure of Example II of application Serial No. 657,629 in 3'75 parts of dioxane heated to 8090 C. at such a rate that the internal temperature does not exceed 0 C. After the addition is complete, the stirring is continued at 0 C. for four hours, then at room temperature for four hours. The mixture is diluted with two liters of water which are added carefully and the yellow product is filtered and washed with water. The yield of air dried material is quantitative. Crystallization from benzene gives 200 parts of pure amido acetal melting at 96 C. Analysis, calculated for C2cH230sN3S: S=6.3; N=8.34. Found: S=5.6; N=8.41.

m-[p- 5 benzoxy-3-methyl 1 pyrazolynbenzenesulfonzzmido] benzaldehyde To a solution of 250 parts of the above amido acetal of this example in 400 parts of acetone at room temperature is added 125 parts of hydrochloric acid and the solution is stirred at room temperature for one hour. After standing overnight at 5 C., the mixture deposits fine light yellow crystals which are filtered and dried. The

yield of crude amidoaldehyde melting at'159- 162 C. is 230 parts. Crystallization from acetone gives 200 parts of purified material melt- C. Analysis, calculated for EXAMPLE I]! m- [p -(5-benzo.ry 3 methyZ-1-pyra2olyl) phenoscyacetamido] benzaldehyde To a stirred suspension of 8.5 parts of maminobenzaldehyde ethylene glycol acetal, 20

parts of water, 10, parts of dioxane, and '7 parts of anhydrous potassium carbonate cooled to 0 "6 C. is added dropwise to a solution of 18.6 parts of 1-(4'-chloroformylmethoxyphenyl) +3-methy1- 5-pyrazolylbenzoate (prepared after the manner described in Example IVof application Serial No. 657,629) in 50 parts of dioxane at such a rate that the internal temperature does not exceed 0 C. Stirring is continued for two hours at 0 C. and for two hours at 25 C. After dilution of the reaction mixture with 400 parts of water, the oil is separated and dissolved in methylene chloride. Crystallization from benzene of the residue after removal of the methylene chloride gives a crystalline material melting at -116 C. Hydrolysis of the amido acetal essentially as described in Example II gives the amidoaldehyde.

EXAMPLE IV 'A suspension of 5 parts of 1-(4'-carboxyphenyl)-3-methyl-5 pyrazolone in 10 parts of acetic anhydride containing a trace .of sodium acetate is heated gently until a homogeneous solution is obtained. Thea'cetic acid and excess acetic anhydride are "removed by distillation under reduced pressure on a steam bath. The resulting 1- (4'-carboxyphenyl) -3-methyl5-pyrazolyl acetate is dissolved in ether and 3 parts of 'thionylchloride are added. A vigorous reaction occurs and hydrogen chloride and sulfur dioxide are evolved. The mixture is refluxed gently for an additional period of 15 minutes during which time the evolution 01 gases ceases. The ether is removed by evaporation and the 1-(4'-chloroformylphenyl -3-methyl-5-pyrazolyl acetate is added to a suspension of 3 parts of m-aminobenzaldehyde dimethyl acetal-in a solution of 3 parts of potassium carbonate in 30 parts of water cooled to 5 C. The mixture is shaken vigorously and after severahminutes the reaction product is-separated, washed free with water, and then with ether. .The reaction product is dissolved in alcohol and an aqueous alkaline. developer solution of p-aminodiethyl aniline is added. A

piece of bleached black and white film is color developed in this solutionv of color former and developer. Removal of the metallic silver gives .a strong magenta image.

. ExAruPLn V m- [p- 5 -benzoxy-3-: methyl- 1 -pyrazolyl) beneamido] benzoldehyde mixture of seven parts of anhydrous potassium carbonate, 50 parts of water, 8.5 parts of m-aminobenzaldehyde ethylene glycol acetal, and 15 parts of dioxane cooled to 24 C. by external cooling. After stirring tor a period 'of three hours at this temperature, the crystalline product is collected and is" washed with cold water. Crystallization from alcohol yields long thin needles melting at 164- 165 C. A solution of the amidoacetal in acetone is treated with 10% hydrochloric acid as described in Example I and the colorless needles are collected, washed with water, and crystallized from a mixture of acetone and alcohol. m- [p-5-benzoxy-3-methyl-l-pyrazolyl)benzamidolbenzaldehyde melts at 174-176 C. Analysis calculated for C25H1904N32 0:70.57; H=4.51; N=9.88. Found: 0:70.40; H- '-4.60,

,"no- 3,3-diethoxypropane, 1

' ibenedmidbl benz wl dchyda ethylene glycol a'cetal c 7 1-- To astirred suspension of 6 parts of m -aminobenzaldehyde ethylene glycol acetal, 25 parts of water, 25'parts of dioxane; and departs of anhydrous potassium carbonate cooleditoo C. was Y 1 m-Ip- (-r-ethylcarbonato-l phenyl 3. -'pz]2:azoZyZ) benzamidolbenzaldehyder 1 V The crude acetal prepared "as described above was-dissolved in, 00 parts of acetonathesolutionjwas heatedto 40 Q. and""7,0' parts of' 3 N hydrochloric acid added with stirring. After cw" minutes; t e m x fei s .qeel dto byyth'e addition o f flicefthecrystalline product was collectedgwashed free of acid and crystallized from benzene; The yield of colorless fine needles meltingfat' 1 84 1V8 5 .5:C;;Was i6 partsl Analysis, calculated; for cztHziOsNs Ni- 9.23. FOiJIldZ 9117; 9.42. In-place' of the specific;5 acyloxypyrazoles 'contaming an acid halide group inithe' lor 3-posi-' tion described above, there inay -be used for amidation of the aminoaldehydesor aminoacetals other compounds of this type including those obtainable'by the processes taught in application Serial No. 651629; Among s'uch useful additional 1 acid chlorides .are ,1-Q2 -ch1oroformylpheny1)'-3furyl 5-p razoly1; benzenesulfonate, ;l'-(4'chlorosu1fonaphthy1-1) 3 inethylr -py fa olvl ethyl carbonate, (6-cholorsulfonaphthy1- 2') -3-phenyl-5-pyrazolyl acetate, and 1- (4!;chlo- 7 other aminoacetals; including m aminobenzaldehyde- A dimethyl acetal", p-aminobenzaldehyde" ethylene glycol acetal, o-aminobenzaldehyde, diethyl acetal, 1-amino-2,2-diethoxyethane,- I-ami- (4 -ami-nophenoxy) jaz-diethox thane, l -Q iramindphenyl), :az-ai- "methoxyethane, 2-chloro-4-amino benzaldehyde reaction;

'dimethyl acetalg i-rnetnoxy-a-a mob n ig hyde ethylene-glycol acetal.

The acetals .of aminoaldehydes. are normally used because 0? their greater stability as opposed to 5 the; aminoaldehydes themselves. However, where-the amino-aldehydes areisufliciently stable they may be used directlyin, the, amidation Although is possible to prepare. 5-acyloiigzpyrazoles; containing more than one aldehyde flor ;aceta1)=-group per molecule, the compounds which contain only; :one aldehyde or acetal group 7 are 7 ."Preferred. Among the additional compounds chsuch as sodium bicarbonate and 'potassiumbicartainable in accordance with the invention are;

, A 1 As indicatedin the examples; analkali metal carbonate is:thepreferredreag'ent for neutralization offthe hydrogen chloride formed by thereaction of the acid chloride and'the-amine; --Other reagents which will react withior' neutralize i hydrogen chloride include organic'compounds' which have. a basic, nitrogen atom containing. e re-' placeable-basic hydrogen atoms such. as pyridine,

quinoline, dimethylaniline, trmiethylamine, m,

ethanolamine, etc. "alkali near bicarbonate-s,

bonate;- alkali earth" carbonates; 3 and bicarbonates. Alkali metal 'salts' of organic acids, such sodium" format a1sobeused:"'- a 'Although the "animation may be carriedout Within'a wide range of temperatures; it'is practical to carry out the rea'ction'in the temprature range of J;0 'to 40- C. At'lower temperatures the reaction becomes "unduly slow; whereas "at 'higher temperatures side reactions such as' hy- .7 drolysis ofthe acid halides before-reaction With the amine and hydrolysis oft-he 5-acy1oxypyrazole become appreciable, thereby decreasing theyield of the desiredproductg 7 a The preferred ratio of reactants is one chemiamine, and 1 toi1.5 chemical equivalents are; re-

agent capable" ofv reacting with or-neutralizi'rig the I 7 potassium acetate, etc, may

9 hydrogen halide liberated during the reaction. It is also possible to carry out the reaction in media other than water-dioxane. Other water-organic solvent systems include water-acetone, water-alcohol, water-benzene, water-ether, etc.

The conversion of the amidoacetals to amidoaldehydes can be accomplished by any of the known methods for hydrolysis of acetals to aldehydes which involves treatment of an aqueous solution or suspension of an acetal with a mineral acid, such as hydrochloric acid, sulfuric acid, phosphoric acid, etc. or with other acids, 6. g., ptoluenesulfonic acid. As indicated in the examples, the hydrolysis may be carried out rapidly at temperatures of about 40 C. or slowly at lower temperatures. In any case only a small amount of mineral acid is required. Higher reaction temperature-s and hydrogen ion concentrations are to be avoided as they cause undesirable side reactions, such as splitting of the -acyloxypyrazoles.

Aldehydes and acetals containing a 5-acyloxypyrazole nucleus as defined in this application are important intermediates in the preparation of polyvinyl acetals. They are also useful in photographic emulsions as color formers and can serve as dye intermediates for the dyeing of cotton, wool, nylon, cellulose acetate, and other synthetic fibers and fabrics. They couple readily with the oxidation product of a para-phenylenediamine developer to give blue, red, or magenta dyes and with diazo compounds to give red or yellow dyes.

As many widely different embodiments of this invention can be made without departing from the spirit and scope thereof, it is to be understood that the invention is not to be limited except as defined by the claims.

What is claimed is:

1. Compounds taken from the group consisting of 5acyloxypyrazoles which are unsubstituted in the 4-position and contain an amidoaldehyde group in at least one of the positions 1 and 3 in the pyrazole ring and their acetals with alkanols of 1 to 4 carbon atoms and 1,2- and 1,3- dihydroxyalkanes of 2 to 4 carbon atoms, and are free from amido-aldehyde reactive groups.

2. Compounds taken from the groups consisting of 5-acyloxypyrazoles which are unsubstituted in the 4-position and contain an amidoaldehyde group in one of the positions 1 and 3 in the pyrazole ring and their acetals with alkanols of 1 to 4 carbon atoms and 1,2- and 1,3-dihydroxyalkanes of 2 to 4 carbon atoms, and are free from amido-aldehyde reaction groups. 1

3. 5-acyloxypyrazoles which are unsubstituted in the 4-position and contain an amide-aldehyde group in at least one of the positions 1 and 3 in the pyrazole ring and are free from amido-aldehyde reactive groups.

4. fi-acyloxypyrazoles which are unsubstituted in the 4-position and contain an amido-aromatic aldehyde group in one of the positions 1 and 3 in the pyrazole ring and are free from amido-aldehyde reactive groups.

5. Compounds taken from the class consisting of amidoaldehydes 01' the formula:

HC-C-R" R Y o 'c' I r -Y-NH-B-GHO wherein Y is a. member taken from the group consisting o1 carbonyl and suli'onyl radicals; RY is an acyl radical: R is a divalent organic radical linked by hydrocarbon carbon atoms to the cyclic nitrogen atom and Y; R" is a monovalent hydrocarbon nucleus and B is a divalent organic radical linked by hydrocarbon carbon atoms to NH and CH0, and their acetals with monohydric alcohols of 1 to 4 carbon atoms and dihydric alcohols of 2 to 4 carbon atoms.

6. Compounds taken from the class consistin of amidoaldehydes of the formula:

wherein Y is a member taken from the group consisting of carbonyl and sulfonyl radicals; RY is an acyl radical; R is a divalent organic radical linked by hydrocarbon carbon atoms to the cyclic nitrogen atoms and Y; R" is a monovalent hydrocarbon nucleus and B is a divalent organic radical linked by hydrocarbon carbon atoms to NH and CH0, and their acetals with monohydric alcohols of 1 to 4 carbon atoms and dihydric alcohols of 2 to 4 carbon atoms.

'7. The 5-acyloxypyrazole amidoaldehyde acetals of the formula:

m c-( wont R-YOC 0- Hz wherein Y is a member taken from the group consisting of carbonyl and sulfonyl radicals; R is an alkoxy radical of 1 to 2 carbon atoms; A is a divalent hydrocarbon nucleus which is attached to the l-nitrogen atom" through an aromatic hyiirocarbon radical and B is a phenylene radcal.

8. The process which comprises reacting a 5- acyloxypyrazole which is unsubstituted in the 4- position and is free from amido-aldehyde reactive groups and contains an acid halide radical taken from the group consisting of carboxylic and sulfonic acid halides in one of the positions 1 and 3 in the pyrazole ring with an acetal of an aminoaldehyde with an alcohol taken from the group consisting of monohydric aliphatic alcohols of 1 to 4 carbon atoms and dihydric aliphatic alcohols of 2 to 4 carbon atoms.

9. m- [p-(5 ethylcarbonato 3 methyl-l-pyrazglyl l)benzamidolbenzaldehyde ethylene glycol ace 9.

10. m-[p-(5-benzoxy 3 methyl-l-pyrazolyl) benzenesulfonamidolbenzaldehyde ethylene glycol acetal.

11. m- ['p-(5 ethylcarbonato 1 phenyl-3-pyrazglyl l)benzamidolbenzaldehyde ethylene glycol ace a.

ELMORE LOUIS MARTIN.

REFERENCES CITED The following referenlces are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,320,422 Frohlich June 1, 1943 FOREIGN PATENTS Number Country Date 27,485 Great Britain Mar. 12, 1907 547,064 Great Britain Aug. 12, 1942 Certificate of Correction tatent No. 2,476,987 I July 26, 1949 ELMORE LOUIS MARTIN It is hereby certified that errors appear in the printed specification of the above numbered patent requiring correction as follows:

Column 6, line 33, Example IV, after formylphenyl insert a closing parenthesis;

column 7, line 43, before 9.17 insert N=; line 56, for roformylmethohyphenyll read roformylmcthoxyphenyl); column 8, line 17, in the formula, for C H OOCCC read C H OOOOC column 9, line 46, for the Word groups read group; line 53, for reaction read reactive; column 10, line 29, in the formula, for AYNHBC read A-YNHBCH;

and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 10th day of January, A. D. 1950.

THOMAS F. MURPHY,

Assistant Uommissioner of Patents. 

